We seek to obtain basic information concerning the function of catecholamines in the central nervous system. We believe that central catecholamine-containing neurons may mediate the cognitive and locomotor components of "arousal" that are fundamental properties of motivated behavior and characteristic manifestations of higher mental activity. Our research will focus on the role of certain prominent catecholamine projections (especially the nigrostriatal dopamine fibers and the dorsal norepinephrine bundle) in feeding and drinking behaviors, but our findings should extend to more general considerations of motivated behaviors. Because of the unique function of central catecholamine systems that we perceive, we expect that following experimental lesions compensations will occur within the damaged system (as in the autonomic nervous system). Thus, at the synaptic level we will examine the mechanisms by which central catecholamine systems adapt to partial damage and we will compare these changes with those observed in other studies in which the intact systems are activated by acute or chronic regulatory imbalances. In short, we will be studying the regulation of synaptic transmission in central fiber systems and their significance to animal behavior, and our data should permit insights into the workings of these systems in intact and brain damaged animals as well as provide an outline of aspects of the neurophysiological bases of motivated behavior. Given the importance of the fiber systems we will be studying, our research, while of a rather basic nature, should have considerable significance for problems related to mental health and cerebral dysfunctions, including Parkinson's disease and mental retardation. BIBLIOGRAPHIC REFERENCES: Kapatos, G., and Zigmond, M. Synaptosomal synthesis of dopamine from L-tyrosine and L-phenylalanine. Fed. Proc. 34, 1975; Heffner, T.G., Zigmond, M.J., Stricker, E.M. Brain dopamine involvement in amphetamine-induced anorexia. Fed. Proc. 34, 1975.